(1) Field of the Invention
At the time of initial building, renovating, or commissioning of an industrial facility it is important to ensure that all field devices such as pressure transducers, flow meters, and various other regulating or measurement devices are properly configured for their intended monitoring and/or reporting functions. All of these field devices must be preconfigured and calibrated before installation for their prescribed application. When errors occur, either in the application of the field device, or by the incorrect configuration of a field device, the results can be damaging, expensive, or even injurious to work personnel.
It is very common at industrial facilities that multiple devices of the same type may function in a variety of applications and locations. If, for instance, a pressure transmitter calibrated at 50 psi maximum is mistakenly placed in an application calling for regulating fluid pressure at 200 psi, it may take considerable time and resources to track down this mistake. This could also indicate that the unit designated for regulating at 200 psi has been installed at another, unknown location. Or, perhaps, the 50 psi device was set up incorrectly by the factory or the plant installation crew. In either scenario, it would take further troubleshooting to pinpoint the cause, naturally resulting in additional commissioning time.
As another example, a field device is initially preconfigured and calibrated. During commissioning of the facility, the configuration of the device is found to be valid but a routine test reveals the device is out of tolerance and requires calibration. This change in the desired calibration may have occurred during shipment or installation. During installation, the most common causes for such a problem are over-tightening, accidentally dropping the device or, in some cases, incorrect orientation within its immediate physical location.
HART-enabled 4-20-mA field devices can prevent errors like these. In such devices, the standard 4-20 mA analog data acquisition channel is supplemented by a digital channel supporting read/write access of data relating to a field device. With HART-enabled software, field devices are configured and calibrated at the time of installation, minimizing errors and commissioning time, or any other time as deemed appropriate by the owner. Briefly, the HART Communication Protocol (Highway Addressable Remote Transducer) defines a bi-directional field communication protocol standard for instrument, control and automation devices and systems. It is a global standard for sending and receiving digital information across analog wires between smart devices and host systems and is supported by leading instrmentation and control suppliers such as ABB, Emerson, Honeywell, Siemens and many others. A host can be any software application, including, but not limited to, a technician's hand-held device, a laptop, or a plant's process control computers, its asset management system, or any other system utilizing a control platform.
It must be appreciated that it takes considerable resources (including but not limited to manpower, time, and equipment) to configure hundreds, or even thousands of field devices in a single facility. The inventive concept presented herein generally relates to an apparatus and a method to consolidate all the components and circuitry required to provide the necessary power required for a HART 2-wire field device, communicate with it, and provide necessary interconnections to the device, with minimal wiring to the device reducing overall time requirements in order to facilitate the configuration.
(2) Description of the Related Art
Currently, end users attempting to configure 2-wire field devices using the HART protocol require a nominal 24-volt DC power supply, a HART network load, and numerous connections to the device, such as a milliamp meter, a HART communicator, or a HART PC modem. The plurality of connections requires time to arrange, invites the possibility of connection errors, and makes a standardized configuration process difficult to achieve. There is no known self-contained device that performs the functions as described in this disclosure, rather, such functions are generally performed by manual manipulation of the various connectors, lead wires, meters, and other equipment necessary to achieve the same results.
There are various mechanisms and systems in current use that are effective at regulating power to a field device, remotely managing a field device, or tracking and providing an alert of maintenance problems pertinent to field devices.
In a published patent application US 2004/0199681, the inventor (Hedtke, 2004) devised a two-wire process transmitter for use in monitoring an industrial process which includes HART communication circuitry and an alternative second configuration with a second pair of electrical terminals to couple Fieldbus communication circuitry to the two-wire process control loop.
U.S. Pat. No. 6,697,684 (Gillen, 2004) discloses a programmable field measuring instrument comprising a power assembly, a connector terminal, and a software protection device. The field device may thus transmit not only its conditioned measuring signal but also other functionalities or data, as programmed by the power assembly.
The inventor in U.S. Pat. No. 7,167,537 (Loechner, 2007) devised a valve controller with a 4-20 mA input interface circuit capable of communicating with a two-wire loop. The invention also comprises a processor that communicates data with the interface circuit, which processor is operable to generate a control signal for controlling the valve position.
U.S. Pat. No. 6,959,356 (Packwood, et al, 2005) features a multi-protocol smart field device which uses a Fieldbus communication protocol to communicate process control information and uses a HART communication protocol to enable local configuration of the field device via a hand-held HART communicator.